The ecteinascidins are exceedingly potent antitumor agents isolated from the marine tunicate Ecteinascidia turbinata. One of these compounds, ET-743 of formula:
is being employed as an anticancer medicament, under the international nonproprietary name (INN) trabectedin, for the treatment of patients with advanced and metastatic soft tissue sarcoma (STS) after failure of anthracyclines and ifosfamide, or who are unsuited to receive such agents, and for the treatment of relapsed platinum-sensitive ovarian cancer in combination with pegylated liposomal doxorubicin.
Ecteinascidin 736 (ET-736) was first discovered by Rinehart and features a tetrahydro-β-carboline unit in place of the tetrahydroisoquinoline unit more usually found in the ecteinascidin compounds isolated from natural sources; See for example Sakai et al., Proc. Natl. Acad. Sci. USA 1992, vol. 89, 11456-11460.

U.S. Pat. No. 5,149,804 describes Ecteinascidin 736 (ET-736), isolated from the Caribbean tunicate Ecteinascidia turbinata, and it structure. ET-736 protects mice in vivo at very low concentrations against P388 lymphoma, B16 melanoma, and Lewis lung carcinoma.
WO03014127 describes several synthetic analogues of ET-736 and their cytotoxic activity against tumoral cells. In particular, WO03014127 describes compounds A to D together with their cytotoxic activity against a panel of cancer cell lines.

Another compound described in this patent application, PM01183, is currently in clinical trials for the treatment of cancer. PM01183 has the following chemical structure:

PM01183 has demonstrated a highly potent in vitro activity against solid and non-solid tumour cell lines as well as a significant in vivo activity in several xenografted human tumor cell lines in mice, such as those for breast, kidney and ovarian cancer. PM01183 exerts its anticancer effects through the covalent modification of guanines in the DNA minor groove that eventually give rise to DNA double-strand break, S-phase arrest and apoptosis in cancer cells.
Despite the positive results obtained in clinical applications in chemotherapy, the search in the field of ecteinascidin compounds is still open to the identification of new compounds with optimal features of activity, selectivity toward the tumour, with a reduced systemic toxicity and/or improved pharmacokinetic properties.